This product is made completely of wood and consists of a board of 12 squares x 18 squares with the numerals 1-18 printed across the top, a box containing 9 red and 9 blue strips of varying lengths, printed with the numerals 1-9, and a box containing 18 natural strips of varying lengths. The Subtraction Board provides the child with practice in working out the subtraction tables from '1-1' to '18-9' systematically and in understanding them.